Positron Emission Tomography in the Neuroimaging of Autism Spectrum Disorder: A Review

Abstract

Autism spectrum disorder (ASD) is a basket term for neurodevelopmental disorders characterized by marked impairments in social interactions, repetitive and stereotypical behaviors, and restricted interests and activities. Subtypes include (A) disorders with known genetic abnormalities including fragile X syndrome, Rett syndrome, and tuberous sclerosis and (B) idiopathic ASD, conditions with unknown etiologies. Positron emission tomography (PET) is a molecular imaging technology that can be utilized in vivo for dynamic and quantitative research, and is a valuable tool for exploring pathophysiological mechanisms, evaluating therapeutic efficacy, and accelerating drug development in ASD. Recently, several imaging studies on ASD have been published and physiological changes during ASD progression was disclosed by PET. This paper reviews the specific radioligands for PET imaging of critical biomarkers in ASD, and summarizes and discusses the similar and different discoveries in outcomes of previous studies. It is of great importance to identify general physiological changes in cerebral glucose metabolism, cerebral blood flow perfusion, abnormalities in neurotransmitter systems, and inflammation in the central nervous system in ASD, which may provide excellent points for further ASD research.

High definition transcranial direct current stimulation of the Cz improves social dysfunction in children with autism spectrum disorder: A randomized, sham, controlled study

“…Cerebral circulation hypoperfusion is a key problem worthy of attention, but it has been minimally studied. Low perfusion is mainly in the frontal lobe, temporal lobe, cerebellum, and limbic system (Tan et al, 2022). The common hypoperfusion brain region is basically consistent with the “social brain” region proposed by Brothers in 1990, which involves human social cognitive function.…”

Dopamine D2R and opioid MOR availability in autism spectrum disorder

“…Moreover, a complementary search with Google Scholar was conducted to confirm that no studies were missing. Finally, we screened three of the latest review articles on the issue to ensure the full coverage of our research [16,53,54]. Altogether, we found nine potentially eligible articles [55][56][57][58][59][60][61][62][63], but only six included requisite data on striatal ROIs.…”

“…Functional magnetic resonance imaging (fMRI) studies in humans have suggested that the dysfunction of the MCL is associated with ASD [12][13][14][15]. Human positron emission tomography (PET) studies have further shown deviant dopamine signaling in ASD compared to controls, but the results have been controversial [16,17]. There is also support for dopamine dysregulation in ASD from genetic studies [18].…”

Candidate biomarkers in psychiatric disorders: state of the field

“…Magnetic resonance spectroscopy (MRS) studies have suggested possible regional changes in GABA or glutamate levels, though findings are inconclusive 75,76 . Positron emission tomography (PET) and single photon emission computed tomography (SPECT) studies have indicated decreased serotonin receptor 5‐HT 2A binding 77 , which could inform treatment studies using medications that block 5‐HT 2A in addition to other receptors.…”